1. Technical Field
The present invention relates to a process for producing expandable potato-based pellets and, in particular, to a process for producing expandable potato-based pellets using a twin screw extruder. The process produces shelf stable products that can be later processed into finished snack chips.
2. Description of Related Art
The process for producing pellets as generally adapted in the food industry involves a very minimal cook of starch and forming a shape, such as a particular pasta shape, wherein the product is later cooked in the presence of excess water. The cooked mass is sheeted, cut, and dried for later frying.
Known processes for producing potato-based pellets do not provide for making a finished product having a shaped surface beyond a simple curve or wave. Further, known processes utilizing twin screw extruders do not provide for a potato-based pellet product wherein embossing helps increase products surface area whereby a finished product has improved oil gain and increased flavor impact.
Typical pellet or half-products require two steps to produce a finished snack product. In a first step, the ingredients, which generally include cereal products and starches, are hydrated to form an extrudable mixture. During extrusion, the ingredients are partially gelatinized creating dough, which is passed through a die. The dense sheeted material, which contains from about 20 to about 40% moisture by weight, is then cut into pellets (with or without lamination) and processed through a dryer to arrive at a final moisture of about 10 to about 14%. This product can then be stored and later processed after moisture equilibration. The potato-based product produced utilizing a single screw extruder will not have a desirable texture, a significant expansion upon cooking, and significant storability. Further, single screw extruder processes are operated at temperatures sufficiently low that allow microbial growth. This requires frequent equipment stoppage to allow for cleaning.
Accordingly, a need exists for a process for making a potato based pellet that has significant storability, improved shape, texture, and flavor while being easily manufactured.
The invention comprises a process for continuously producing a potato based expandable pellets. The potato base comprises potato flakes, which include potato granules to provide enhanced potato flavor, and starch, which generally includes potato, modified potato, and corn starch. Additionally, salt and emulsifier are added to the potato base thereby forming a potato flour mixture. The potato mixture is then passed through a preconditioner for mixing, hydration, and partial thermal cooking.
After being hydrated, the potato mixture becomes a free flowing dough and is routed through a twin screw extruder. The extruder first mechanically shears and cooks and then cools the meal before passing it through a die to form a thin wide ribbon. The ribbon is split into two individual ribbons for treatment. The treatment involves perforating and stretching each ribbon prior to laminating the ribbons together. The ribbons are then cut into pellets with the perforated surfaces forming the exterior of the pellets.
Once the pellets are formed, they are transferred to a series of dryers. The first dryer is a shaker dryer that prevents formation of clusters during the initial drying phase. This is followed by passing the pellets through a short dryer where pellet moisture is reduced without hardening the surface. To reduce the pellet moisture further, a finishing dryer dries and tempers the pellets. The dried pellets are then ready for packaging for later production by, for example, flying, air puffing, or microwave cooking.
The above as well as additional features and advantages of the present invention will become apparent in the following written detailed description.